1. Field of the Invention
The present invention relates generally to plasma etch methods employed for fabricating microelectronic products. More particularly, the present invention relates to plasma etch methods employed for efficiently fabricating microelectronic products.
2. Description of the Related Art
Common in the art of microelectronic product fabrication is the use of plasma etch methods. Plasma etch methods often provide efficient methods for etching various types of materials within microelectronic products.
While plasma etch methods are clearly desirable and often essential for fabricating microelectronic products, plasma etch methods are nonetheless not entirely without problems. In that regard, it is often difficult to provide plasma etch methods with enhanced endpoint detection.
It is thus towards the goal of providing plasma etch methods with enhanced endpoint detection that the present invention is directed.
Various plasma etch methods having desirable properties have been disclosed in the art of microelectronic fabrication.
Included but not limiting among the plasma etch methods are plasma etch methods disclosed within: (1) Cain, in U.S. Pat. No. 5,242,532 (a two step plasma etch method and related endpoint detection method); (2) Tang et al., in U.S. Pat. No. 6,211,092 (a counterbore plasma etch method applicable to dual damascene structures); and (3) Zhu et al., in U.S. Pat. No. 6,297,163 (an additional plasma etch method applicable to dual damascene structures).
Desirable for microelectronic product fabrication are additional plasma etch methods with enhanced endpoint detection.
It is towards the foregoing object that the present invention is directed.
A first object of the present invention is to provide a plasma etch method for etching a microelectronic layer.
A second object of the present invention is to provide a plasma etch method in accord with the first object of the present invention, wherein the plasma etch method provides for enhanced endpoint detection.
In accord with the objects of the present invention, the present invention provides a method for etching a silicon oxide containing layer with respect to a silicon nitride etch stop layer.
To practice the present invention, there is first provided a substrate having formed thereover a silicon nitride etch stop layer in turn having formed thereupon a silicon oxide containing layer. There is then etched the silicon oxide containing layer while employing a plasma etchant gas composition comprising octafluorocyclobutane and oxygen without an added carbon and oxygen containing gas. Finally, there is determined an endpoint within the plasma etch method by monitoring a change in concentration of the carbon and oxygen containing gas.
The present invention provides enhanced endpoint detection within a plasma etch method for etching a microelectronic layer.
The present invention realizes the foregoing object within the context of etching a silicon oxide containing layer with respect to a silicon nitride etch stop layer by: (1) etching the silicon oxide containing layer while employing a plasma etch method employing an etchant gas composition comprising octafluorocyclobutane and oxygen without an added carbon and oxygen containing gas; and then (2) determining an endpoint within the plasma etch method by monitoring a change in concentration of the carbon and oxygen containing gas.